I was watching Biogen’s stock (BIIB) climb over 100 points yesterday because its Alzheimer’s drug, aducanumab [brand name: Aduhelm], received surprising FDA approval. I hadn’t been following the drug at all (it’s enough to try and track some Covid treatments/vaccines). I knew only that the FDA panel had unanimously recommended not to approve it last year, and the general sentiment was that it was heading for FDA rejection yesterday. After I received an email from Geoff Stuart[i] asking what I thought, I found out a bit more. He wrote: Continue reading
The replication crisis has created a “cold war between those who built up modern psychology and those” tearing it down with failed replications–or so I read today [i]. As an outsider (to psychology), the severe tester is free to throw some fuel on the fire on both sides. This is a short update on my post “Some ironies in the replication crisis in social psychology” from 2014.
Following the model from clinical trials, an idea gaining steam is to prespecify a “detailed protocol that includes the study rationale, procedure and a detailed analysis plan” (Nosek et.al. 2017). In this new paper, they’re called registered reports (RRs). An excellent start. I say it makes no sense to favor preregistration and deny the relevance to evidence of optional stopping and outcomes other than the one observed. That your appraisal of the evidence is altered when you actually see the history supplied by the RR is equivalent to worrying about biasing selection effects when they’re not written down; your statistical method should pick up on them (as do p-values, confidence levels and many other error probabilities). There’s a tension between the RR requirements and accounts following the Likelihood Principle (no need to name names [ii]). Continue reading
For Statistical Transparency: Reveal Multiplicity and/or Just Falsify the Test (Remark on Gelman and Colleagues)
Gelman and Loken (2014) recognize that even without explicit cherry picking there is often enough leeway in the “forking paths” between data and inference so that by artful choices you may be led to one inference, even though it also could have gone another way. In good sciences, measurement procedures should interlink with well-corroborated theories and offer a triangulation of checks– often missing in the types of experiments Gelman and Loken are on about. Stating a hypothesis in advance, far from protecting from the verification biases, can be the engine that enables data to be “constructed”to reach the desired end .
[E]ven in settings where a single analysis has been carried out on the given data, the issue of multiple comparisons emerges because different choices about combining variables, inclusion and exclusion of cases…..and many other steps in the analysis could well have occurred with different data (Gelman and Loken 2014, p. 464).
An idea growing out of this recognition is to imagine the results of applying the same statistical procedure, but with different choices at key discretionary junctures–giving rise to a multiverse analysis, rather than a single data set (Steegen, Tuerlinckx, Gelman, and Vanpaemel 2016). One lists the different choices thought to be plausible at each stage of data processing. The multiverse displays “which constellation of choices corresponds to which statistical results” (p. 797). The result of this exercise can, at times, mimic the delineation of possibilities in multiple testing and multiple modeling strategies. Continue reading
David Mellor, from the Center for Open Science, emailed me asking if I’d announce his Preregistration Challenge on my blog, and I’m glad to do so. You win $1,000 if your properly preregistered paper is published. The recent replication effort in psychology showed, despite the common refrain – “it’s too easy to get low P-values” – that in preregistered replication attempts it’s actually very difficult to get small P-values. (I call this the “paradox of replication”.) Here’s our e-mail exchange from this morning:
Dear Deborah Mayod,
I’m reaching out to individuals who I think may be interested in our recently launched competition, the Preregistration Challenge (https://cos.io/prereg). Based on your blogging, I thought it could be of interest to you and to your readers.
In case you are unfamiliar with it, preregistration specifies in advance the precise study protocols and analytical decisions before data collection, in order to separate the hypothesis-generating exploratory work from the hypothesis testing confirmatory work.
Though required by law in clinical trials, it is virtually unknown within the basic sciences. We are trying to encourage this new behavior by offering 1,000 researchers $1000 prizes for publishing the results of their preregistered work.
Please let me know if this is something you would consider blogging about or sharing in other ways. I am happy to discuss further.
David Mellor, PhD
Project Manager, Preregistration Challenge, Center for Open Science
David: Yes I’m familiar with it, and I hope that it encourages people to avoid data-dependent determinations that bias results. It shows the importance of statistical accounts that can pick up on such biasing selection effects. On the other hand, coupling prereg with some of the flexible inference accounts now in use won’t really help. Moreover, there may, in some fields, be a tendency to research a non-novel, fairly trivial result.
And if they’re going to preregister, why not go blind as well? Will they?
Mayo Continue reading